Prime Directive
by Almedha
Summary: When a strange malfunction pulls the Enterprise and Defiant into a strange new universe, they find themselves entrenched in a battle between a technologically inferior species and alien parasites.
1. Chapter 1

_This story was a request from Just a Crazy-Man. In short, while fighting a squadron of Jem'Hadar fighters, a mishap pulls the Enterprise-D and the Defiant into another reality. (I do label this as a DS9-SG-1 crossover because I'm more interested in the DS9 characters than I am the TNG characters, even though they are present, as well.) I'm flying this crazy ship by the seams of my command uniform, so comments, critiques, and the like are very welcome and appreciated. I hope you like it!_

_As per the usual: none of the characters and _et cetera_ are owned by me._

_I will continue update this, but only as often as I am inclined. At this point in time, "SG-1's Long Trek Home" is a priority to me. _

* * *

**Chapter 1**

"Nog," Jadzia laughed from her seat at the console. Poor little Ferengi, she thought. He hadn't stopped shaking since Benjamin had called him up to join them on the Defiant in defense of Deep Space Nine. They just didn't make Ferengi commandos, she thought with a smile. "Calm down. There's nothing to be worried about."

"I'm not worried," Nog hissed, and licked his sharp teeth. She could hear them grinding all the way across the bridge.

She laughed again and shook her head, but fell silent when she heard the door slide open and the rest of the crew filtered in. First, Kira and Benjamin came in. She smiled at them, and Benjamin flashed that signature smile at her. Jadzia thought that if he hadn't been preoccupied with his conversation with the Major, he would have greeted her with the familiar "old man" sobriquet.

Next in came Chief O'Brien and Doctor Bashir. They were arguing, as usual, about some holosuite program they were running at Quark's. Jadzia didn't think it was polite to listen in on their conversation... even though that wouldn't have usually stopped her. Julian and Miles took their seats on the opposite side of the bridge.

They had halted their conversation and decided not to continue when they saw that Jadzia was watching them. "Any luck saving the Kobayashi Maru?" she asked with a trite smile. Their fascination with no-win scenarios as an avenue of entertainment was only slightly disturbing to her. Although, she had to admit she partially saw the appeal, she liked to know that she could win, also.

"Has nothing to do with the Kobayashi Maru," Julian corrected, looking slightly confused.

"I think that was a metaphor, Julian," Miles pointed out.

"Of course, it was," Julian agreed with a nod, and then squinted at Jadzia. "We were training for this mission," he explained.

When Miles snorted, Jadzia smiled. "So the wall defenses of the Alamo are going to help us somehow?" she guessed. "Maybe the bottle-necked valley of the besieged Three-Hundred Spartan warriors." Julian looked at Miles, looking very interested, but Miles shook his head emphatically.

"No Spartans, Julian," Miles scolded.

Julian shrank into his chair and objected, "I haven't got a program like that anyway." Then he looked at Jadzia, adding, "But I will!" Miles rolled his eyes, apparently not happy with the way this conversation was going. Jadzia, personally, saw nothing wrong with the Battle of Thermopylae.

"Let me know when you do," Jadzia told him. "I'd love to join you."

She knew that Benjamin would put a stop to their babbling chatter very soon, and, as soon as Worf shuffled in, fussing at his Klingon warrior's baldric, he did.

"Dax!" he trumpeted. She looked at him and waited. "Hail the Enterprise."

Jadzia went to it immediately and, soon enough, the face of Jean-Luc Picard, captain of the Enterprise, flashed onto the screen. Jadzia wondered if Benjamin really appreciated working with Captain Picard, but decided that Benjamin was nothing if not professional. Although, he could get a little emotional about things sometimes. By the time she was drawn out of her nostalgic reverie, she had missed half of the conversation.

"The Redding and the Discovery should be able to help with that," Benjamin said.

"Agreed." Captain Picard turned to one of his crew and then back to the screen. "They will stay in formation until the order to break."

"Understood," Benjamin said.

"And you will give that order, Captain," Captain Picard went on. "As the lead vessel."

"Yes, sir," Benjamin agreed. He nodded to Dax and she terminated the contact. Benjamin settled into his captain's chair and then turned his face, now serious, to their newest crewmember. "Ensign Nog," he said.

"Yes, sir!" Nog piped.

"Take us away from Deep Space Nine... toward the Cardassian border... Warp two." Benjamin pondered, and Dax relayed the message to the seven other ships in their attack group. The Cardassians, the Federation had gotten word, was coming. The best course of action at this point was to cut them off before they arrived in full force—show them what they could do. Jadzia was all for that. She didn't want the Cardassians any closer to Deep Space Nine than they already were.

When the Cardassian/Jem'Hadar fighter group showed up on sensors, Jadzia thought that starships two lightyears over could have heard Nog's announcement about it. Benjamin looked at Nog pointedly and said, "Thank you, Ensign." Nog looked down at his console and became very, very quiet. In fact, the entire bridge did... except for Jadzia.

Jadzia tried to hide her smile, but Kira, who was sitting next to her, got a very good view of it. Fortunately, Kira thought Nog's enthusiasm was as funny as Jadzia did. They were kindred spirits in wartime, it seemed. Dax's Klingon-warrior tendencies and Kira's Bajoran Freedom Fighter past gave them both insight into battle that the others didn't have, except maybe O'Brien. Then again, O'Brien did have a family, and Jadzia didn't envy him the sick worry she knew that came with mixing battle out here and family back home.

"Ensign, slow to one-quarter impulse," Benjamin ordered to Nog, while Jadzia relayed the order. "Let's creep up on them..."

"Aye, sir," Nog agreed.

He was obviously tempering his tone very carefully, since Nog did tend to squeak when he got nervous. Nog must have thought that Starfleet officers never squeaked... but Jadzia found it easy to forgive the young man his lack of experience with other, rarer alien species. She might have to tell him later that Ferengi weren't the only species in the galaxy that squeak when nervous—not by a longshot.

And creep they did. The Cardassians and the Jem'Hadar, judging by sensors, seemed very confused when they slowed. Their wheeling and spiraling dots on the sensors sometimes darted forward as though on the attack, then pulled back. Jadzia could hear Nog breathing deeply, staring at his console, waiting for his next order. Jadzia looked back at her own communication's panel. Listening and following orders... that was the only way she'd gotten through her first battle.

As soon as Benjamin judged they were close enough, he announced, "Full impulse, attack pattern beta." Nog carried out the orders while Jadzia forwarded the message. The ships struck forward in unison, clashing phasers and cannons creating fireworks in the dark void. The Defiant shook.

Fortunately, the Defiant could deal damage just as well as she took it. She was a warship, after all. Her phasers flew, dotting the void with bright orange fireballs that disappeared in an instant as Jem'Hadar fighters exploded. The attack pattern of starships flew like streaking ribbons of blue light. Dax looked up just in time to see the Enterprise's phasers chop the wing off a Jem'Hadar fighter. It spiraled and went flying.

* * *

The interior of the tel'tak fell totally silent… Jonas wasn't sure if that would assist in their attempt at hiding from the Goa'uld motherships looming just outside, but it was worth a try. Was he even holding his breath? He sighed and leaned forward to look out the window at the enormous pyramidal ships, two of them, just sitting there… Sitting there looking for them.

He looked at Sam and then at Jacob. Or perhaps Selmac. Goa'uld were weird like that—Tokra. Tokra. He had to keep reminding himself of that. The Tokra were liable to be offended at being compared to their evil cousins… or whatever. In any case, he was way more interested in staying alive to watch another day of the weather channel than being zapped to a neat little crisp in space.

But he'd always wanted to go on an awesome rescue mission… an awesome any-mission. He was sick of sitting around at Stargate Command with Doctor Jackson's books. He was just as useless as a fly on the wall. And most of the time he wasn't even that. He was a fly shut up in the closet where he couldn't bother anyone.

"I don't think they're just going to give up," Sam whispered.

"Of course, not." So it was Selmac. Of course, it was. It seemed to Jonas, from mission files, that Selmac was the one to usually pilot a tel-tak. He could only guess it was because he had a few hundred years of experience over Jacob. "But neither are we."

At least that was something, Jonas thought. Teal'c and Jack were down there, investigating rumors of Ba'al's presence on this far-flung planet with two other SG teams, one of which had come back through earlier and sent them on this ridiculous rescue mission.

Jonas thought he must have looked unconvinced, since Sam was saying a moment later, "We didn't come all this way to leave them there. This just put a… a wrench in the plan."

Selmac paused and Jacob was talking once again in his usual voice. "It's not like Ba'al to broadcast his presence blatantly. We did expect this."

"Because two Goa'uld motherships are subtle," Jonas filled in sarcastically. On what planet?

Jacob looked up over his shoulder at Jonas as though to say, _Who invited the new guy?_ Or, maybe he was just imagining that. In any case, Sam smiled at Jonas and put her hand on her father's shoulder. "There must be a way to get past them without drawing attention."

Jacob looked up at his daughter, the look on his face not one so encouraging. Jonas sighed as Jacob said, "I'm all for ideas…"


	2. Chapter 2

_Thank you for the reviews! Many apologies for my lack of attention to this tale._

_EDIT: Thank you so much to the reader who pointed out that the _Defiant_, in fact, has five decks. The situation has been corrected._

_ANOTHER EDIT: Thank you again, everyone, for your reviews! They are greatly appreciated! Since I have gotten a few about how overpowered the Star Trek ships are in comparison to the Goa'uld ships, I'll explain my reasoning and hope it helps and/or makes some marginal sense. Honestly, I have no idea how the liquid naquadah staff cannons on a ha'tak compare to phasers. So here's what I do know: staff cannons have little effect on Asgard shields, so it is possible to stop them with shielding advanced enough. __ Phasers, according to Star Trek ("The Outrageous Okona"), are laughably overpowered versions of lasers, which exist in the Stargate universe as Asgard _laser cannons (according to the Stargate RPG, as it is never stated explicitly what Asgard weapons actually are in the TV show that I know of...) that are a match for Goa'uld motherships, if not better because the Asgard are technologically superior to the Goa'uld. Because Star Trek ships have weapons more advanced (assuming lasers are the same in both universes, since both universes attempt to be somewhat realistic) than the Asgard, I have to assume they could totally out-class a Goa'uld ship in firepower. Inexplicably, however, the Goa'uld ships are faster, as it is explicitly stated in both series just how fast_ the respective ships can go. Um...__In short, if lasers are equal to staff cannons and phasers are greater than lasers, then phasers must be greater than staff cannons._

* * *

**Chapter 2**

The _Defiant_ bucked and shuddered as each new projectile jarred the shields and hull. Jadzia's fingers made claws on the console in front of her, but that didn't help much on the clear, smooth surface. "Deck 2 is reporting casualties!" Julian shouted, trying to rise from his seat, but falling back down into it when the _Defiant_ shook again.

"Mr. O'Brien!" Benjamin shouted.

"Shields are holding steady, sir!" Miles returned.

"Then let's show those Jem'Hadar what this ship can do…" Benjamin growled. "Nog!" The little Ferengi looked up from his chair, his face set determinedly to not look frightened, but his eyes betrayed him. Jadzia looked back at her console quickly to watch the fleet's movements. "Bring us about."

Jadzia watched Nog's fingers fly over his control panel and his teeth grind under the strain of trying to stay upright in his seat and getting the _Defiant_ to follow ordered like a good girl. "Mr. Worf," Benjamin said once three Jem'Hadar fighters and a Cardassian warship was in view. It was a moment before he said anything—a moment of perfect and total silence. Not even the ship moved.

"Fire."

Mr. Worf looked only too happy to oblige. "Firing."

Photon torpedoes and phasers rocketed away from their ship. The torpedoes found their way to the warship's hull while the phasers clipped one Jem'Hadar fighter before destroying the other two. The warship seemed none the worse for it, though, until an explosion rocked the interior and showed a fireball emerging from the cargo bay doors.

"Finish them, Mr. Worf," Benjamin commanded, though regretfully.

Jadzia couldn't help but think herself: she hadn't joined Starfleet to kill. Though, one expected to have to do such things every few lifetimes or so… She turned her eyes over the bridge crew and thought sadly, none of these lives would ever be washed clear of the stains of war. She was interrupted when her console beeped.

"Benjamin!" Jadzia interrupted, not using his formal name on accident. She partially cringed, but didn't have the time to bother with apologies or any such thing. "Message from Starfleet!"

Benjamin snarled at the viewscreen and then gave the order to see what they had to say. It was an admiral that Jadzia didn't first recognize, but that wasn't unusual. It was supposed to be this admiral's first fleet action command from the big chair—that is, the chair bigger than the one the captains sat in. "Captains, Commanders," the admiral said with a nod. He was obviously, Jadzia thought, grinding her teeth, not in the middle of a battle.

"Admiral," Benjamin returned under his breath.

"It's a trap," the admiral said. "The Cardassians and Jem'Hadar attacking Deep Space 9 are a diversion. We are forwarding the location of their new target. Now…" the admiral went on just before Benjamin could voice his concern about leaving the station to be destroyed. "Only take as many ships as you think you will need, Captain Picard and Commander Sisko."

"Yes, sir," Captain Picard's voice said.

"Yes… sir…" Benjamin agreed, also, obviously thinking. Jadzia's mind worked, too. Leaving Deep Space 9 in the hands of a dozen well-armed starships wasn't so bad. But she wondered about their destination… She pulled up the communique and looked at it.

"Commander Sisko, we will leave immediately," Captain Picard informed him as soon as the admiral went to attend to other situations. He paused a moment and then went on, "Commander Johnson, as well."

Jadzia singled out the three ships on her screen. The _Defiant_, the _Enterprise_, and the _Redding_. The three of them were among the most advanced in the Federation's fleet, and could surely take on a small contingent of Jem'Hadar and Cardassians on their own.

"Nog," Benjamin trumpeted a moment later. "Set the course and get us on our way."

"Aye, sir," Nog agreed, tapping feverishly into his console.

"Warp seven."

"Warp seven, aye."

"The _Enterprise_ and _Redding_ are ready, sir," Jadzia reported.

Jadzia wasn't sure what happened then, but it wasn't what she had expected. Together, the three ships entered warp and then were suddenly jarred out of it. They weren't where they were supposed to be, that was for certain. Benjamin stood from his chair and took one step toward the view screen.

She looked up and felt her jaw drop. Everyone else, Jadzia imagined, across all three Federation ships were doing the same thing. She looked around at her dumbstruck colleagues before looking back at the screen. "What the hell?"

* * *

"What in the world is that?" Jonas asked as the flash of light dissipated to show three new ships looming in the darkness. Sam squinted at them and Jacob tilted his head to one side like a confused puppy. Not necessarily great responses to his totally serious question…

Jacob considered a moment before answering, "They aren't like any ships I've ever seen."

Sam shook her head in agreement. They were small, Jonas first noted. Silver. The largest of them was like a mere ant to the Goa'uld mothership. And they all three knew that any moment from now, a battle could break out. If Jonas was a betting man, he might have placed all of his chips on the Goa'uld.

Jacob was looking at the sensor readings of the alien ships. "Their weapons, their communications… they are so different from ours, I don't know if we could send a message to them or not."

"Not that we would," Sam muttered. "Unless we wanted every system lord in the galaxy to know we were here."

They all fell silent once again, waiting for something to happen. The Goa'uld, all of them knew, wouldn't just sit there staring for long. If these aliens were a threat to their power—and who knew if they were or not?—they'd never stand for it.

All at once, bright fireworks set off in space as the Goa'uld seemed to make their decision. Energy weapons pummeled the ships again and again, sparking in bubbles around the ship before dissipating, it seemed, harmlessly. The little ships just sat. If ships could laugh, these three just might be. Mocking them. A moment later, a red ribbon of light sliced into the Goa'uld ship like a knife, slicing off a chunk of the corner.

"What is that?" Sam marveled.

"I have no idea," Jacob answered.

Jonas just watched, dumbfounded for the moment. "I hope they're friendly."


	3. Chapter 3

_A little bridge chapter so you know I still live. _

_Thank you to every last one of you who have reviewed and read this story! I only hope this thing lives up to your expectations._

* * *

**Chapter 3**

"Nog," Benjamin snapped. "Where are we?"

Nog was already tapping feverishly at his controls to figure that out, hissing like a Dalvin beetle. "I don't know, sir," Nog answered before he had finished. Or perhaps he had finished. Jadzia looked down at her own computer panel and saw that all of the familiar markings of Federation space—star bases, outposts, regularly occurring transmissions flying back and forth in subspace—were not there. "We have arrived at the coordinates you ordered, sir."

"Then what are those?" Benjamin asked, turning back to the view screen and looking at the alien vessels just sitting there. One of them was missing a little off its corner, but the other was untouched.

"They are unlike any vessel I have ever seen and there is no record of a vessel of this configuration," Worf offered. "Scans indicate no signs of a warp drive, no subspace communication system… There are humans aboard, sir. Humans and… other lifeforms. No less than a thousand combined," he added, and then looked at the computer as though it confused him.

"Thank you, Mr. Worf," Benjamin muttered, probably thinking that he could have told that by just looking at the thing.

Except the humans. That was interesting, Jadzia thought. The computer beeped pleasantly at her and she spun in her chair. "The _Enterprise _and the _Redding_ are hailing us," Jadzia said.

"On screen," Benjamin ordered, and the screen was split between the images of Captains Picard and Johnson.

"Captain," Captain Picard said with a nod at each of them. "What do you make of this?"

Benjamin shrugged helplessly while Captain Johnson tumbled over a few words, essentially saying he had no idea, either. "Sir!" Jadzia said, looking down at her readouts. "The alien ships are moving away. Approximately at warp… very fast," she finished.

Benjamin raised an eyebrow at her, almost smiling. "Very fast, old man?"

"Approximately 32,000 times the speed of light," Jadzia explained after the computer had finished calculating.

"My god," Julian whispered.

"That's impossible," Benjamin insisted a moment later.

"Obviously not," Picard sighed. "Wherever we are now is certainly not where we were. Suggestions?" he asked the two captains, and then looked back at his first officer. Benjamin did the same, looking at Kira. Kira looked positively stunned, but immediately took control of herself and shook her head.

"Captain," Worf spoke up. "A much smaller ship." He stopped as, once again, the computer seemed to confuse him. "Just on the other side of that moon," he offered finally.

"What is it doing?" Benjamin asked.

"Nothing," Worf answered. "It may be scanning us. It may be readying weapons. There is no way to tell until we know more about these vessels."

"Hail it," Benjamin ordered.

Jadzia looked up at him with a small smile, about to tell him that it probably wouldn't work, but Worf tried hailing anyway. As she suspected, nothing. "There are three humans and another alien lifeform on board. The atmosphere in the smaller ship is obviously breathable," she added.

Benjamin caught her in a look of disbelief. "You've got to be joking, old man," Benjamin hissed.

Jadzia shrugged. "I don't see any other way to figure out what's going on. We can't communicate with them other than face-to-face." Picard pinched his lips and shook his head. Captain Johnson just shrugged. "What other way is there?" she asked.

"First contact is not a thing to be taken lightly, Lieutenant Commander," Picard scolded.

That may have been true, she thought with a smile. But after a few lifetimes, Captain Picard might have changed his mind about things he took so seriously. "But, at present," he added, "I see no other option." He looked back at his first officer again. "Commander Riker, assemble—"

"Captain," Benjamin cut in, much to Jadzia's relief. She was already half-rising from her seat.

She was certain she had more experience than all of the officers on any of their ships. Even though Captain Picard was a seasoned diplomat, and Jadzia had spent one of her lifetimes rampaging through glorious battle with a couple of Klingons… In any case, she thought she was more than qualified to go on this away mission.

"Perhaps we shouldn't be so hasty," Captain Johnson pointed out.

"The other option is that we sit here staring at each other," Benjamin said. "I'd like to go with the Commander, Captain."

"No, I think it'd be best if you stayed on the _Defiant_," Captain Picard said solemnly. "We have no idea what might be over there and we do not need to lose any of our ships' captains."

"Lieutenant Commander?" Dax spoke up.

"Dax?" Benjamin asked, as though he thought she were interrupting something. She didn't get a chance to continue, because Benjamin went on, "Captain, I would like to send Lieutenant Commander Dax along on this away mission." When Captain Picard looked to be about to ask why, he explained, "None of my bridge officers can beat seven lifetimes of conversation experience."

"This is not just any conversation…" Captain Picard muttered. "Captain Johnson, would you select one of your crew? We will beam them over from the _Enterprise_."

* * *

"Do you think they see us?" Jonas wondered.

"They shouldn't," Jacob answered. "I think we ought to get Jack and Teal'c and get out of here."

"But—but—" Sam stammered, pointing at the three ships sitting just outside their window… as though they didn't know what she was talking about. "What are they? What if they turn out to be a worse threat than the Goa'uld? We have to find out something more about them."

"Sam," Jacob interrupted. "We can figure out these problems later."

"Well," Jonas offered, gesturing weakly at the ships, "I doubt Ba'al will be back anytime soon. I mean, that was ridiculous."

Jacob nodded in agreement, but didn't get a chance to say anything further. There was the sound of wind-chimes, or chinking crystal, or something like that, and all three of them whirled around to figure out what in the world it was. Three beings appeared, all looking mostly human; and, for a moment, they all stood staring at each other.

Just as Selmac whirled about, leveling a zat'nik'tel at the intruders, Sam reached for her own gun, and Jonas stepped forward with his hands up. "I'm Jonas," he said, trying on a smile even though he wasn't exactly feeling it at the moment. "Who are you three, what are you doing here—"

"And how did you get here?" Selmac finished.

The leader of the group, Jonas guessed, the one with the beard, held his hands out to show that they were empty and that he, supposedly, had no weapons. Not any that Jonas was familiar with anyway.

"I'm Commander Riker," he said. "Lieutenant Commanders Dax and Lee," he added, pointing out his companions, the woman with spot tattoos first and then the other man. "We don't mean anyone any harm."

"We saw what your ship did to the Goa'uld vessel," Sam said.

"Pretty harmful," Jonas muttered.

The one Commander Riker pointed out as Lieutenant Commander Dax spoke next. She had a pretty voice, so pretty that Jonas almost didn't notice that she was, in fact, speaking English like he, Sam, and Jacob were. "Our ships were caught in some sort of…" She waved her hands briefly in a gesture that Jonas took to mean she had no idea what in the world they were caught in.

"We aren't supposed to be here," Riker finished for her.

"We've never seen ships like yours before," Sam offered.

"And we've never seen ships like yours," Dax agreed with a smile. "But we seem to be in the right place, just maybe not…" Her voice trailed away and Riker, once again, picked up where she left off.

"We are from a federation of planets," Riker started. "As Lieutenant Commander Dax said, we seem to be in the right place, but if you could tell us where we are, it might help us."

"We're in orbit around P3S-114," Sam answered. "A planet controlled by the Goa'uld, Ba'al."

Riker and his companions exchanged glances, mouthing the words "P3S-114" and "Goa'uld" to each other. Meanwhile, the mention of the planet's designation brought something different to mind for Jonas. "Sam?" he asked, easily catching her attention even though there were things much more interesting going on. "Jack and Teal'c?"

"Jack and Teal'c…" Sam sighed, looking at Jacob.

Jacob shrugged. "We have to go ahead as planned."

"Who are Jack and Teal'c?" Riker requested.

"Friends of ours held captive by the Goa'uld on the planet," Sam explained. "We were about to go on a rescue mission when the motherships showed up."

"And then you showed up," Jonas finished. "And you know the rest."

Riker looked at Dax, and then Dax looked at Jacob with a slight smile. "We might be able to help with that."

"In exchange…" Riker put in.

"For what?" Sam asked warily.

"Information."


End file.
